FunctionalJ is a library for writing functional style code in Java. It aims be a practical expansion to functional programming added in Java 8. FunctionalJ is a pure Java library with all code written in Java so its usages will be just like other Java library. No additional build steps or tools are required outside of adding dependencies. FuncionalJ works with Java 8 and up.

  void Employee(
          String firstName,
          String lastName) {}
  void Department(
          String   name,
          Employee manager) {}

  val departments = FuncList.of(
          new Department("Sales",   new Employee("John", "Doe")),
          new Department("R&D",     new Employee("John", "Jackson")),
          new Department("Support", new Employee("Jack", "Johnson"))
  // Prints: [Doe, Jackson, Johnson]

The code above show a few feature of FunctionalJ. One is the Struct type. Struct annotation generate a value object class which are immutable and null strict. Struct also comes with lens (which is seen used in the code as well), quick validation and exhaustive builder. Another feature shown here is the lazy-evaluated immutable functional list. Learn more at


DefaultJ is a Java library to provide a default value of any class. It support multiple strategies of getting the default value. It can be use as a simple but powerful dependency injection utility. In that aspect, it injects value base on the class, very much similar in principle with Guice. How DefaultJ has may ways specifying default value. And this is done within the code without external configuration. Even better, the code can specify the way to use default without depending on DefaultJ. Only when a code requries the default value, DefaultJ is then needed.

public class Car {
    public static Car newInstance() { return new Car(); }
    public String go() {
        return "Zoom!";

public class Driver {
    private Car car;
    public Driver(Car car) { = car;
    public String drive() {
        return car.go();

Car myCar = DefaultProvider.instance.get(Car.class);
assertEquals("Zoom!", myCar.go());

Driver myDriver = DefaultProvider.instance.get(Driver.class);

As you can see, DefaultJ can get default values of the Car and Driver. In case of Car, since there is @Default on a static method that return Car, DefaultJ use that to create an instance. In case of Driver, its has a constructor requiring a Car instance so DefaultJ create a Car instance and use that to create a Driver instance. Calling default constructor is one of the strategy DefaultJ uses. Factory method is another strategy. DefaultJ has 14 built-in strategies for getting default values. More detail about those strategies are discussed below.

It is important to note that DefaultJ does not require the annotation @Default to be from DefaultJ. The annotation can be from any package. It just has to have RUNTIME retention. This allow any code to specify default value providing strategy without depending on DefaultJ.


Java Uitility used to deal with ‘null’. It is designed to used with Lombok @ExtensionMethod (see here and here). This means it will be the most beneficial when used with @ExtensionMethod although you can use the utilities without that. The use of Lomlok’s extension methods particularly magnify the value of null-safty done to all the utility methods. For example, you can write code like this…

// string CAN BE NULL.
return string._whenMatches("^[0-9]+$").map(Integer::parseInt).orElse(-1);
//            ^^^^^^^^^^^^

The above code parse the string to an int or return -1 if the string is null or does not contains an integer.


RiotComponent adds methods, properties or events to the root element so that it can be accessed from the outside. Methods allow the parent element to call functions in the child elements. Properties expose settable values of the child elements to the parent. When set the child will be notified so that appropirate actions (such as update) can be done. Events will allows the child elements to notify the parent element when something happened. Plus! In the line of the minimalist approach of RiotJs, the RiotComponent is sized less than 1K!

<count-down id='count' label='Count: ' start=5></count-down>

... the 'count-down' tag code is absent for brevity. ... 

var count = document.getElementById('count')
// Use `on(...)` to listen to event `zero`.
count.on('zero', function() {
    alert('It is ZERO!')
    // `label` is a property, changing it here trigger an update. 
    count.label = prompt('Enter new label (or "STOP at " to stop the timer): ', "STOP at ")
    if (!(count.label === 'STOP at ')) {
        // `restart()` is a callable method to restart the counter.

Try the above out here Live demo on jsFiddle


RiotAutoMount listen to element insert event and check if the inserted element is a riot element. If it is, riot.mount(...) will be run on it. Simply import the script.

<script src="riot-automount.min.js"></script>


npm install riotautomount


LayoutMode helpes to organize CSS rules for resposive website.

LayoutMode allows CSS rules to be organized into modes which are in turned controlled by media query. In the nute shell, LM decouple media query and the CSS rules. With LM, media queries can be created to select named modes. The modes are, then, translated to classes of body element. The actualy style CSS rules can then be tided to the modes of the body.


{MediaQuery} ==> {CSS rules}

With LM

{MediaQuery} ==> {modes (body.mode-XXX)} ==> {CSS rules}

As the mode appears the class on the body element, you can use that as a qualifier to style anything under body ... and that is everything.

You can also have multiple mode at the same time as they are independent. For example, you may have 'compact' and 'spacious' for different resoluation and also have 'normal-contrast' and 'high-contrast' for font size and color scheme. Then at one time, the mode might be ['spacious', 'high-contrast'].

Try the above out here Live demo on jsFiddle